<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        .container{
            padding: 1px;
            background: #123;
            border: 1px solid #456;
            width:450px;
        }
        .div{
            width: 150px;
            height: 150px;
            background: #987;
            float: left;
            margin: 10px;
        }
    </style>
</head>
<body>
    <div class="container">
        asdfghj dfghkjlsdfgh sdfhgj
        <div class="div"></div>
        <div class="div"></div>
        <div class="div"></div>
        <div class="div"></div>
        <!--<p style="clear: both">zxcvb xfghjc sdfghn</p>-->
    </div>
    加边框不会形成BFC

</body>
</html>